1. Field of the Invention
This invention relates to a novel deashed coal obtained by oxidizing coal with aqueous nitric acid, separating from the resulting product an aqueous phase and a solid phase, extracting the solid phase with a solvent and then heating the extract to remove volatile material therefrom.
2. Description of the Prior Art
Ash (inorganic components which will not burn when coal is subjected to combustion) can be removed from coal by heating a coal slurry with hydrogen at elevated temperatures and elevated pressures for a time sufficient to liquefy the coal and then subjecting the hydrogenated product to filtration to remove the solids (ash) therefrom. Although the process is effective for its intended purpose the cost of such removal is high because of the large amounts of hydrogen consumed and because of the high temperatures and high pressures required. It would be highly desirable, therefore, to find an alternative process for deashing coal.